Chapter 6 Scientific Revolution During the 16th and 17th centuries, a few European thinkers questioned classical and medieval beliefs about nature, and developed a scientific method based on reason and logic. It began with astronomy. In the 2nd century Ptolemy had explained the movements of the planets, sun, and moon, placing the earth at the center of the universe. This geocentric model required very complex models to explain the planets' retrograde motion. He offered no proof, or any explanation for why the planets moved, but his system was accepted throughout the Middle Ages, until humanists began to question classical authority. Nicolaus Copernicus (1473 1543), a Pole, proposed a heliocentric model, placing the sun at the center. It was a more satisfying explanation for planetary motion, but he offered no proof. Johannes Kepler (1571 1630), a German, was an assistant to Tycho Brahe, the Danish astronomer who had compiled the most accurate and comprehensive star charts based on naked eye observation. Kepler explained planetary orbits mathematically, without explaining why they moved. He calculated their relative speeds, and that their orbits are elliptical. 1
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Galileo Galilei (1564 1642), an Italian, was the first astronomer to use a telescope. He discovered previously unknown stars, Jupiter's moons, and Saturn's rings. His discoveries confirmed the validity of the Copernican model, and that there was more in the universe than could be observed with the naked eye. The Catholic Church put Galileo on trial for contradicting the Bible and placed him under house arrest. It was the first example in the West of a Christian church challenging a scientific discovery. Isaac Newton (1642 1727), an Englishman, discovered why the planets move, and how they move, by formulating the laws of gravity and of motion. He also invented calculus, and discovered the laws of optics. Newton showed the possibilities of the human mind. Using reason and math, he figured out how the universe worked. His laws showed the universe worked like a machine. It was no longer a mystery, and a mechanistic view of the universe began to prevail. Francis Bacon (1561 1626), an English philosopher, developed the scientific method based on induction (from specific evidence to a general theory). This involved gathering data, experimenting, forming a hypothesis, and then formulating a theory. Bacon saw science as something useful and practical, as something that can improve the human condition. Aware of all the new geographic discoveries, he rejected relying on classical authorities in science. 3
Rene Descartes (1596 1650), a French philosopher and mathematician, invented the Cartesian coordinate plane. He was a proponent of deduction (from a general statement to specific examples), which is not however used in science today. He had a mechanistic view of the universe and believed it could be understood mathematically and rationally, while accepting the existence of God, which he deduced. "Cogito, ergo sum" (I think, therefore, I am) means that the ability to reason proves existence and reality. Thomas Hobbes (1588 1679), an English political philosopher, was the author of Leviathan. He had a materialistic view of history and of human nature. He made no reference to God or to the human soul and took a scientific approach. His theories were therefore not based on references to divine right nor to traditional medieval arrangements. He believed humans are selfish and interested in maximizing their own pleasure, which means that in a state of nature (before the existence of government) life, "nasty, brutish, and short," would be a war of all against a Government is therefore a result of a covenant between people and their ruler, and it is established to control us. He rejected hereditary inequality. H nonetheless believed that government must have absolute, unchallenged authority in order to control us and maintain order, and so his arguments justified royal absolutism. 4
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John Locke (1632 1704), an English philosopher, believed humans are born naturally good and a blank slate (tabula rasa), rejecting original sin. He believed humans are born with rights and that these natural rights include "life, liberty, and property." He believed people create their government, rejecting divine right, but that it exists to protect and secure those rights. Unlike Hobbes, he believed the authority of government should be limited. Locke believed that government requires the consent of the governed, so if government abuses the people's rights, then the people have the right to change their government. It is therefore licit to overthrow a tyrant by force. Locke supported religious tolerance, and believed no government has authority to determine people's religion. Authentic religious faith cannot be imposed. Instead, it must be in accord with one's conscience. He makes exceptions to his support for tolerance, however, for Catholics, because they owe allegiance to a foreign ruler, and atheists, because they cannot be trusted as citizens due to their absence of morality derived from God. 6
Anatomical and medical discoveries by physicians presented the body as an integrated system, challenging the traditional humoral theory of the body and disease espoused by Galen. In the 17th century William Harvey, for example, discovered the circulation of blood in the body and the functions of the heart, New institutions were established in Europe outside of universities where scientists could share their discoveries and receive support and criticism from their peers. Examples include the Royal Society of London (1660) and the French Academy of Sciences (1666). They received government support because science offered practical discoveries which could improve economic productivity or increase military power. These institutions brought together people from different social classes. Despite the Scientific Revolution alchemy and astrology continued to appeal to elites and some natural philosophers, in part because they shared with science the notion of a predictable and knowable universe. Newton, for example, sought the philosopher's stone throughout his career. In the oral culture of peasants, a belief that the universe was governed by divine and demonic forces persisted, which explains the contuned belief in witchcraft. 7